Composer is vulnerable to Command Injection via Malicious Perforce Repository

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Summary

CVECVE-2026-40176
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-15 21:17:27 UTC
Updated2026-04-17 15:38:09 UTC
DescriptionComposer is a dependency manager for PHP. Versions 1.0 through 2.2.26 and 2.3 through 2.9.5 contain a command injection vulnerability in the Perforce::generateP4Command() method, which constructs shell commands by interpolating user-supplied Perforce connection parameters (port, user, client) without proper escaping. An attacker can inject arbitrary commands through these values in a malicious composer.json declaring a Perforce VCS repository, leading to command execution in the context of the user running Composer, even if Perforce is not installed. VCS repositories are only loaded from the root composer.json or the composer config directory, so this cannot be exploited through composer.json files of packages installed as dependencies. Users are at risk if they run Composer commands on untrusted projects with attacker-supplied composer.json files. This issue has been fixed in Composer 2.2.27 (2.2 LTS) and 2.9.6 (mainline).

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS: 0.000100000 probability, percentile 0.009690000 (date 2026-04-20)

Problem Types: CWE-20 | CWE-78 | CWE-20 CWE-20: Improper Input Validation | CWE-78 CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Composer Composer affected >= 2.3, < 2.9.6 Not specified
CNA Composer Composer affected >= 1.0, < 2.2.27 Not specified

References

ReferenceSourceLinkTags
github.com/composer/composer/releases/tag/2.9.6 [email protected] github.com
github.com/composer/composer/security/advisories/GHSA-wg36-wvj6-r67p [email protected] github.com
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